IBM Opens Its Quantum-Computing Stack To Third Parties

An anonymous reader quotes a report from Ars Technica, written by John Timmer: [P]art of the software stack that companies are developing to control their quantum hardware includes software that converts abstract representations of quantum algorithms into the series of commands needed to execute them. IBM's version of this software is called Qiskit (although it was made open source and has since been adopted by other companies). Recently, IBM made a couple of announcements regarding Qiskit, both benchmarking it in comparison to other software stacks and opening it up to third-party modules. [...] Right now, the company is supporting six third-party Qiskit functions that break down into two categories.

The first can be used as stand-alone applications and are focused on providing solutions to problems for users who have no expertise programming quantum computers. One calculates the ground-state energy of molecules, and the second performs optimizations. But the remainder are focused on letting users get more out of existing quantum hardware, which tends to be error prone. But some errors occur more often than others. These errors can be due to specific quirks of individual hardware qubits or simply because some specific operations are more error prone than others. These can be handled in two different ways. One is to design the circuit being executed to avoid the situations that are most likely to produce an error. The second is to examine the final state of the algorithm to assess whether errors likely occurred and adjust to compensate for any. And third parties are providing software that can handle both of these.

One of those third parties is Q-CTRL, and we talked to its CEO, Michael Biercuk. "We build software that is really focused on everything from the lowest level of hardware manipulation, something that we call quantum firmware, up through compilation and strategies that help users map their problem onto what has to be executed on hardware," he told Ars. (Q-CTRL is also providing the optimization tool that's part of this Qiskit update.) "We're focused on suppressing errors everywhere that they can occur inside the processor," he continued. "That means the individual gate or logic operations, but it also means the execution of the circuit. There are some errors that only occur in the whole execution of a circuit as opposed to manipulating an individual quantum device." Biercuk said Q-CTRL's techniques are hardware agnostic and have been demonstrated on machines that use very different types of qubits, like trapped ions. While the sources of error on the different hardware may be distinct, the manifestations of those problems are often quite similar, making it easier for Q-CTRL's approach to work around the problems.

Those work-arounds include things like altering the properties of the microwave pulses that perform operations on IBM's hardware, and replacing the portion of Qiskit that converts an algorithm to a series of gate operations. The software will also perform operations that suppress errors that can occur when qubits are left idle during the circuit execution. As a result of all these differences, he claimed that using Q-CTRL's software allows the execution of more complex algorithms than are possible via Qiskit's default compilation and execution. "We've shown, for instance, optimization with all 156 qubits on [an IBM] system, and importantly -- I want to emphasize this word -- successful optimization," Biercuk told Ars. "What it means is you run it and you get the right answer, as opposed to I ran it and I kind of got close."